The human retroviruses that have been extensively characterized (HTLV-I, HTLV-II, HIV-1, and HIV-2) all have a tropism for the peripheral blood mononuclear cells (PBMC). Serological assays have been used quite successfully to identify persons with prior exposure to these viruses but fail to determine a current infection. virus isolation assays require prolonged co-cultivation of patients' PBMC with a susceptible cell line and have been shown to lack sensitivity. A newly described DNA amplification technique, the polymerase chain reaction (PCR) appears to have a great potential for detection of viral DNA. The PCR however, requires highly trained personnel, expensive equipment and about three days to perform an assay. Microbiological Associates Inc. (MBA) proposes to develop a simple, rapid, hybridization assay to detect current infections by these retroviruses. The method employs a plastic capillary as a solid phase to perform the hybridization assay. The capillary provides a very large reactive surface relative to sample size and also forces the close proximity of reactants. This environment produces increased sensitivity with shorter incubation times and temperature requirements. A non-isotopic, enzyme immunoassay amplification detection system is used to indicate hybridization with a known DNA probe.